The invention is generally directed to a paper feeding apparatus for use in a printer and in particular to a cut sheet feeder which can select an appropriate cut sheet from various types of mounted cut sheets, and feed the appropriate sheet into the printer.
Paper feeding apparatuses are well known in the art and cut sheet feeders are applicable for use with various printers used as typewriters or as word processors. The cut sheet feeders remove the need for an individual to separately align each sheet of paper in the printer or typewriter. Instead, a cartridge tray or other type of paper holding device can be filled with many sheets which are fed singly to the printer at appropriate times. In particular, a single cut sheet feeder has compartments for different sizes of paper further speeding the paper feeding process.
Conventional cut sheet feeders are driven in two different ways. The first type of cut sheet feeder incorporates an electrical selecting element such as a motor or a solenoid. The feeder is directly electrically connected to a printer so that the printer has direct control over the motor or solenoid. The second type of conventional cut sheet feeder provides power to the cut sheet feeder by use of a paper feeding mechanism usually coupled to the printer's platen. The cut sheet feeder is driven by a combination of clockwise and counterclockwise rotation of the paper feeding motor. In both cases, a one-way clutch or a ratchet device is used to prevent the paper feeding assembly from drawing back the sheet already wound into the paper feeding mechanism of the printer.
One-way clutches and ratchets are expensive mechanical elements and result in an increase in the cost of a cut sheet feeder utilizing these elements. The requirement that a cut sheet feeder be powered electrically by the printer increases the complexity of the cut sheet feeder unit and limits its application to printers specifically adapted to control such a cut sheet feeder.
Accordingly, there is a need for a cut sheet feeder which enables selection and feeding of single sheets from a variety of compartments or trays in the cut sheet feeder, powered by a mechanical linkage with the paper feeding mechanism of the printer, and without the need for expensive components such as a one-way clutch or a ratchet.